On the Madden Julian Oscillation – Atlantic Hurricane Relationship

Colorado State University
On the Madden Julian Oscillation – Atlantic Hurricane Relationship

Philip J. Klotzbach*
Department of Atmospheric Science

Fort Collins CO 80523e

Submitted to Journal of Climate: 11 Decembr 2008
Revised: 24 June 2009
Second Revision: 3 August 2009

Abstract
The large-scale equatorial circulation known as the Madden-Julian Oscillation (MJO)has been shown to impact tropical cyclone activity in several basins around the globe. In this paper, we utilize an MJO index created by Wheeler and Hendon to examine its impacts on tropical genesis and intensification in the Atlantic. Large differences in frequency and intensity of tropical cyclone activity are seen, both in the tropical Atlantic as well as in the northwest Caribbean and Gulf of Mexico depending on the MJO phase. Coherent changes in upper-and lower-level winds and relative humidity are likely responsible for these differences. Since the MJO shows potential predictability out to about two weeks, the relationships discussed in this paper may be useful for short-term predictions of the probability of tropical cyclone activity in the Atlantic as a complement to the already available longer-term seasonal predictions.